Tmux

Tmux is one of the widest known terminal multiplexers along with screen. I find it useful when I don’t want to bother with panes in my kitty terminal.

Be aware this configuration is mostly keybinds.

Setting sane configurations

By default, Tmux does not support all the colours your terminal may support, so we need to tell it to set true colours…

set-option -sa terminal-overrides ",xterm*:Tc"

We can also tell it to enable mouse support. That way, we will be able to click on Tmux elements and scroll in its panes!

set -g mouse on

Finally, I’ll set vi-mode for some sane movements.

set-window-option -g mode-keys vi

Windows and panes configuration

Although I agree in computer science most things should begin with zero, I find it quite weird to see my first window and my first pane to be labelled with it rather than one. So, let’s pull a Lua on Tmux and force it to begin with 1 instead of 0.

set -g base-index 1
set -g pane-base-index 1
set-window-option -g pane-base-index 1
set-option -g renumber-windows on

Plugins!

Using TPM, we can use plugins in Tmux! The way I installed it is very simple:

mkdir -p ~/.config/tmux/
git clone https://github.com/tmux-plugins/tpm.git ~/.config/tmux/tpm

Here’s a list of the plugins that I use.

Plugin	Why
tpm	TPM itself
tmux-sensible	Better defaults I can’t be bothered to change myself
tmux-yank	Better copy/pasting
tmux-prefix-highlight	Tell me which prefix I’m using
tmux-resurrect	Persist tmux sessions across system restarts
nordtheme/tmux	Nord theme for Tmux!

(mapconcat (lambda (plugin)
             (format "set -g @plugin '%s'"
                     (if (string-match-p (quote "/") plugin)
                         plugin
                       (concat "tmux-plugins/" plugin))))
           plugins
           "\n")

Let’s run TPM right after that.

run '~/.config/tmux/tpm/tpm'

For restoring processes with tmux-resurrect, we must add additional programs in the @resurrect-processes variable. These are:

• "~ncmpcpp -q"
• btop
• ssh

set -g @resurrect-processes '"~ncmpcpp -q" btop ssh'

Keybindings

Firstly, I don’t like prefixing all of my keybindings with C-b, that’s what I use in insert-mode in Emacs to make the cursor go back. So instead, let’s set meta with space as my prefix.

unbind C-b
set -g prefix M-Space
bind M-Space send-prefix

Now, I will only add few keybindings on the root prefix that actually do something immediately, I will mostly add keybindings that will lead to other prefixes; I prefer by far to have keychords that are a bit lengthy and mnemonic than some obscure “ C-M-& is for doing this and that”.

Keybinding	Command	Prefix to go to
«	select-window -p
»	select-window -n
Tab		windows
w		pane
y		copy-mode

Note I am using the key w to access the pane prefix because of how used to Emacs I am, and in Emacs terminology panes are windows while tmux windows would be tabs.

bind-key -T prefix « select-window -p
bind-key -T prefix » select-window -n
bind-key -T prefix Tab switch-client -T windows
bind-key -T prefix w switch-client -T pane
bind-key -T prefix y switch-client -T copy-mode

Panes

As you will see not only here but also lower, I am not using the usual hjkl to navigate around since I am using the bépo layout. I use instead the ctsr keys.

Below are the keybindings living in the pane prefix. Note that calls to split-window have a -c "#{pane_current_path}" argument so new panes open in the same directory as the directory I am currently in.

Keybinding	Command	Prefix to go to
/	split-window -h -c “#{pane-current_path}”
-	split-window -v -c “#{pane-current_path}”
c	select-pane -L
t	select-pane -D
s	select-pane -U
r	select-pane -R
f	resize-pane -Z
.		pane-resize

bind-key -T pane / split-window -h -c "#{pane-current_path}"
bind-key -T pane - split-window -v -c "#{pane-current_path}"
bind-key -T pane c select-pane -L
bind-key -T pane t select-pane -D
bind-key -T pane s select-pane -U
bind-key -T pane r select-pane -R
bind-key -T pane f resize-pane -Z
bind-key -T pane . switch-client -T pane-resize

When it comes to resizing the panes, the keybindings are in their own prefix referenced above: pane-resize. All keybindings will lead to the same prefix again, which enables the user to type for instance M-Space w . r r r r r in order to call repetitively resize-pane -R 5. Hitting any key that is not part of the current prefix will get us out of it.

Keybinding	Command	Prefix to go to
c	resize-pane -L 5	pane-resize
t	resize-pane -D 5	pane-resize
s	resize-pane -U 5	pane-resize
r	resize-pane -R 5	pane-resize
C	resize-pane -L	pane-resize
T	resize-pane -D	pane-resize
S	resize-pane -U	pane-resize
R	resize-pane -R	pane-resize

bind-key -T pane-resize c resize-pane -L 5\; switch-client -T pane-resize
bind-key -T pane-resize t resize-pane -D 5\; switch-client -T pane-resize
bind-key -T pane-resize s resize-pane -U 5\; switch-client -T pane-resize
bind-key -T pane-resize r resize-pane -R 5\; switch-client -T pane-resize
bind-key -T pane-resize C resize-pane -L\; switch-client -T pane-resize
bind-key -T pane-resize T resize-pane -D\; switch-client -T pane-resize
bind-key -T pane-resize S resize-pane -U\; switch-client -T pane-resize
bind-key -T pane-resize R resize-pane -R\; switch-client -T pane-resize

Windows

Since windows are more akin to tabs in Emacs, and I am way more used to it than Tmux, all keybinds are prefixed with a Tab, itself prefixed with the main prefix.

Keybinding	Command
c	new-window
n	next-window
p	previous-window

bind-key -T windows c new-window
bind-key -T windows n next-window
bind-key -T windows p previous-window

In order to access more easily the different windows, I want to be able to type <prefix> TAB <window number>. However, I’m using the bépo layout, numbers are available only when pressing shift. Otherwise, the characters typed are "«»()@+-/* (from 1 to 0).

(let ((keybinds "")
      (keys '("\\\"" "«" "»" "(" ")" "@" "+" "-" "/" "*")))
  (dotimes (i (length keys) keybinds)
    (setq keybinds (string-trim
                    (concat keybinds
                            "\n"
                            (format "bind-key -T windows %s select-window -t :=%d"
                                    (nth i keys)
                                    (1+ i)))))))

Copy in vi mode

Tmux has a nice mode for vim keybindings users: copy-mode-vi which allows moving the cursor around in the pane, select some stuff, and copy it. But first, I need to unbind some keys:

unbind -T copy-mode-vi H
unbind -T copy-mode-vi J
unbind -T copy-mode-vi K
unbind -T copy-mode-vi L
unbind -T copy-mode-vi h
unbind -T copy-mode-vi j
unbind -T copy-mode-vi k
unbind -T copy-mode-vi l

Keybinding	Command
v	send-keys -X begin-selection
C-v	send-keys -X rectangle-toggle
y	send-keys -X copy-selection-and-cancel
C	send-keys -X top-line
J	send-keys -X jump-to-backward
S	send-keys -X scroll-up
R	send-keys -X bottom-line
T	send-keys -X scroll-down
c	send-keys -X cursor-left
t	send-keys -X cursor-down
s	send-keys -X cursor-up
r	send-keys -X cursor-right

bind-key -T copy-mode-vi v send-keys -X begin-selection
bind-key -T copy-mode-vi C-v send-keys -X rectangle-toggle
bind-key -T copy-mode-vi y send-keys -X copy-selection-and-cancel
bind-key -T copy-mode-vi C send-keys -X top-line
bind-key -T copy-mode-vi J send-keys -X jump-to-backward
bind-key -T copy-mode-vi S send-keys -X scroll-up
bind-key -T copy-mode-vi R send-keys -X bottom-line
bind-key -T copy-mode-vi T send-keys -X scroll-down
bind-key -T copy-mode-vi c send-keys -X cursor-left
bind-key -T copy-mode-vi t send-keys -X cursor-down
bind-key -T copy-mode-vi s send-keys -X cursor-up
bind-key -T copy-mode-vi r send-keys -X cursor-right